A man opened fire on a policeman bringing an eviction order, killing him and another man before he was shot dead by officers.

Police said Thomas Caffall, 35, gunned down Brazos County Constable Brian Bachmann just after noon on Monday as the officer was serving the eviction notice at a house near the Texas A&M University campus. Both men were later pronounced dead at a hospital.

Chris Northcliff, 43, was also killed in the shooting at the off-campus home not far from the university's football stadium, College Station assistant police chief Scott McCollum said. Three other officers and a 55-year-old woman were wounded.

Caffall's sister said that the family was "shocked" by the violence. "Our hearts and prayers go out to the families and this is just a senseless tragedy," said Courtney Clark, from her mother's home in Navasota, about 20 miles to the south. "We are just distraught by the havoc that he has caused."

Officers responding to reports of an officer down saw Constable Bachmann wounded on the ground in the front garden, then got into what Mr McCollum described as an extended shoot-out with Caffall, who was eventually shot.

Police spokeswoman Rhonda Seaton said Mr Northcliff was outside the home when he was shot, as was the wounded woman.

The woman is in hospital in a serious condition following surgery. One of the injured officers, Justin Oehlkee, was treated for a gunshot wound in the calf and was in a stable condition, Ms Seaton said. Two other officers, Brad Smith and Phil Dorsett, were treated for "shrapnel injuries" and released.

Police would not speculate on a motive for the gunfire.

The shootings prompted Texas A&M to issue an emergency alert warning students and residents to stay away from the area. But most of the university's 50,000 students were not on the campus, about 90 miles north west of Houston, because they were on their summer holiday break, university spokeswoman Sherylon Carroll said.

Texas governor Rick Perry, an A&M alumnus, said at an event in Florida that his "prayers are with any of those that have been injured". A&M president Bowen Loftin called Monday a "sad day in the Bryan-College Station community".